Washing machine



cfT. BUTTON WASHING MACHINE June 13, 1967 3 heets-Sheet 1 Filed May 6,1965 June 13, 1967 c. T. BUTTON WASHING MACHINE 3 he'ets-Sheet 2 FiledMay 6, 1965 June 13, 1967 c. T. BUTTON 3,32

WASHING MACHI NE Filed May 6, 1965 3 heets-Sheet 5 United States Patent3,324,690 WASHING MACHINE Charles T. Button, Dayton, Ohio, assignor toTexas I struments Incorporated, Dallas, Tex., a corporation of DelawareFiled May 6, 1965, Ser. No. 453,591 3 Claims. ((3. 68-23) This inventionrelates to washing machines and more particularly to a washing machineactuator employing a mechanically resonant agitator drive.

The development of controllable electromagnetic drive systems which canbe freely reversed or programmed in behavior and the design of suchelectromagnetic structures which can be directly coupled to a washingmachine agitator have made possible the construction of a washingmachine which includes exceptionally few components and which is, forthis reason, relatively simple in construction and reliable inoperation. However, the relatively high peak torque required foragitator oscillation has required that relatively massive actuatorcomponents be employed to provide this torque.

Among the several objects of this invention may be noted the provisionof a washing machine construction in which the peak torque required fromthe drive means is substantially reduced for a given agitator movement;the provision of such a construction in which energy is stored duringnonpeak torque conditions and is expended in providing the desired peaktorque; the provision of such a construction in which the actuator isoperated as a resonant system; the provision of such a constructionincluding an exceptionally simple method of coupling the washing machinebasket to the actuator for a spin dry operation; the provision of such aconstruction which is extremely reliable; and the provision of such aconstruction which is relatively simple and inexpensive to manufacture.Other objects and features will be in part apparent and in part pointedout hereinafter.

A washing machine construction according to the invention will typicallyinclude a tub, an agitator journalled for rotation Within the tub and areversible drive means for oscillating the agitator. In one aspect ofthe invention, the peak torque required from the drive means duringagitation is reduced by operating the agitator as part of a resonantsystem with spring means being provided for storing energy and forapplying a restoring torque at the oscillatory peaks of agitatormovement. In another aspect of the invention, the apparatus alsocomprises a rotatable basket for holding clothes to be washed and thespring means interconnects the agitator and the basket so thatunidirectional rotation of the agitator is coupled to the basket for theextraction of moisture by spinning.

The invention accordingly comprises the constructions hereinafterdescribed, the scope of the invention being indicated in the followingclaims.

In the accompanying drawings in which various possible embodiments ofthe invention are illustrated,

FIG. 1 is an exploded view of the major components of a washing machineof the present invention;

FIG. 2 is an exploded view of the actuator of the washing machine ofFIG. 1;

FIG. 3 is an assembled view of the actuator; and

3,324,69b Patented June 13, 1%67 FIG. 4 is a bottom view of anotherembodiment of the torsion spring means of the actuator.

Referrin now to FIG. 1, the washing machine therein illustratedcomprises a conventional sheet metal cabinet or housing 11. A base plate13 is supported within housing 11 and it is upon this base plate thatthe major clothes washing components are mounted. The base plate 13 isribbed for strength as at 15 and includes a tubular central post 17projecting upwardly therefrom. An actuator 19 is secured to theunderneath side of base plate 11 by screws 21. Actuator 19 is describedin greater detail hereinafter but, for the present, it may be noted thatthe actuator includes a pair of upwardly extending coaxial shafts 23 and25 which project upwardly through spindle 17. The outer tubular shaft 23is shaped at its upper end to engage and rotate with a conventionalwashing machine basket assembly while the upper end of the central shaft25 includes a key slotted portion 26 for receiving a conventionalWashing machine agitator.

A tub 27 is secured to the upper side of base plate 13. As will beapparent to those skilled in the art, tub 27 and base plate 13 willinclude appropriate openings for the necessary water inlets and drainsand suitable fixtures for the mounting of pumps and valves. Theseprovisions, however, are conventional and, since they do not pertain tothe present invention, are not shown or described further herein.

A perforate clothes receiving basket 31 fits within tub 27 and includesa central sleeve 33 which fits rotatably over spindle 17. The upper endof sleeve 33 includes surfaces which mate with the upper end of thetubular actuator shaft 23 so that basket 31 is secured to and is drivenby shaft 23.

An agitator 35 is provided which includes a plurality of radial blades37 and a hollow central post portion 39 which fits loosely and rotatablyover sleeve 33 of basket 31. The upper end of post portion 3a includesan internaL ly slotted part 41 by means of which the agitator can bekeyed to the mating portion 26 of the central actuator shaft 25. Thusthe agitator 35 is secured to and driven by shaft 25. A cap 42 coverspart 41.

The construction of actuator 19 itself can be seen in FIGS. 2 and 3.Mechanical energy for operating the washing machine is obtained from anelectromagnetic device 45 of generally pancake configuration. Device 45includes a stator 47 which is wound with a multiplicity of energizingwindings 49, These windings can be sequentially energized by polyphasealternating or pulsating current to provide a plurality of rotatingmagnetic poles. A squirrel cage rotor 51 is mounted directly on agitatorshaft 25 for rotation within stator 47. While direct connection of rotor51 through shaft 25 to agitator 35 is preferred, this connection canalso be made through appropriate reduction gearing or belting whichprovides a positive mechanical coupling between these elements. A bottomplate 53 covers the underside of electromagnetic device 45 and retains athrust bearing assembly 55 for supporting shaft 25.

The rotor 51 of electromagnetic device 45 can be driven in eitherdirection. A preferred form of electronic control for providingsequential energization of windings 49 in either rotational direction isthat shown in my copending application, Ser. No. 425,265, filed Jan. 13,1965 and entitled, Electromagnetic Apparatus. A reversible DC. motor orother driving source can also be used although it is preferable that anA.C. construction be employed.

Mounted on shaft just above rotor 51 is a crank member 57. Crank member57 is secured against rotation relative to shaft 25 by a screw pin 59which is threaded into member 57 and extends into a transverse bore 61in shaft 25.

The tubular, basket-supporting shaft 23, discussed previously indescribing the overall construction of the washing machine, includes atits lower end a transverse flange 65. Assembled on shaft 23 just aboveflange 65 is a torsion spring assembly 67 which includes a pair ofoppositely wound spiral springs 69 and 71. Springs 69 and 71 are kept intheir proper planes by separator discs 73-75. The inner end of each ofsprings 69 and 71 terminates in a radial key portion, 77 and 79respectively. Key portions 77 and 79 are adapted to fit into theopposite sides of a slot 81 which is cut into a flanged, spring carryinghub 83. Hub 83 is secured against rotation relative to tubular shaft 23by a screw pin 85 which threads into hub 83 and extends into an aperture87 in the side of tubular shaft 23. Thus the inner ends of springs 69and 71 will rotate with shaft 23. The outer end of each spiral spring 69and 71 terminates in a hook portion, 89 and 91 respectively.

A flanged thrust bearing 93 fits within tubular shaft 23 underneathflange 65 and the entire tubular shaft assembly, including the torsionspring components, fits over shaft 25 as may be seen in FIG. 3. Thecoaxial shafts are assembled so that the crank member 57, which rotateswith shaft 25, is engageable with the hook portions 89 and 91 of springs69 and 71. Thus, shaft 25 is resiliently coupled, through springs 69 and71, to shaft 23 or, stated in terms of the overall washing machineconstruction, agitator is resiliently coupled to basket 31. The positionof basket 31 thus establishes the nominal rest position of agitator 35.

It will be apparent to those skilled in the art that the mass ofagitator 35 and attached rotor 51 and the resilience of springs 69 and71 constitute a mechanically resonant or oscillatory system in which thesprings exert a restoring force which tends always to return theagitator to its nominal rest position. Since the rotational inertia ofbasket 31 is typically greater than that of the agitator rotor assembly,the resonant frequency of the agitator system will not be substantiallyaffected by the fact that the inner ends of springs 69 and 71 areanchored relative to basket 31 rather than being attached to some fixedcomponent of the machine. The basket will oscillate somewhat duringoscillation of the agitator but the basket oscillations will, atresonance, typically be small and out-ofphase with the agitatormovements. Any excursions of basket 31 will be further restrained by thepresence of water and clothes within the basket. Optionally, mass may beadded to the basket to modify its behavior. However, if desired, thesebasket oscillations can be eliminated by the addition of a brake or pawlarrangement which locks the basket relative to the housing.

The operation of actuator 19 in the washing machine constructionillustrated is as follows. For agitation, the windings 49 areenergized'in a pattern such that the sequence of energizationperiodically reverses direction of rotation relative to stator 47. Thusrotor 51 is driven first in one direction and then in the other.Agitator 35, being directly coupled to rotor 51 through shaft 25, willexperience the same oscillatory angular excursions. The total torquerequired to produce this oscillatory motion reaches a peak, due to theinertia of the system, just as agitator 35 reverses its direction ofrotation. Since springs 69 and 71 exert a maximum restoring torque atthe peaks of the oscillatory excursions, the amount of torque which mustbe generated electromagnetically is substantially reduced. Thus, theelectromagnetic device need be only of sufficient size to provide theenergy absorbed in the clothes washing operation and does not need to beof such size as would be required to provide the whole peak torqueneeded for reversing the direction of rotation of the agitator in agiven oscillatory motion. Stated in another way, the excursions causedby a given power input to windings 49 are much greater when the agitatoris incorporated into a mechanically resonant system than those whichwould be produced when it is operated free of any resilient restoringforce.

While it is desirable that the agitation be performed at a frequencywhich is at or near a resonant peak, the restoring force exerted by thesprings will provide a considerable reduction in the peakelectromagnetic torque required over an appreciable range of frequenciesor component values. As long as the spring constant is not more thantwice that required for resonance at the desired or predeterminedoperating frequency, an advantage by way of torque reduction isobtained. Stated in another way, a torque advantage is obtained if theresonant frequency is not more than double the operating frequency. Toadjust for the desired effect, the rotational inertia of the variouscomponents and the spring constant can be varied. Typically, it isdesirable to choose these parameters to produce agitator resonance atthe highest frequency of operation contemplated, the torque reductionbeing greatest at resonance. At lower frequencies the peak torquerequired is lower anyway, since the inertia forces are less, so that theelectromagnetic system can supply the necessary torque even though thebenefit obtained through the use of the torsion spring is not as greatas at resonance.

To provide a spin dry operation for the centrifugal extraction ofmoisture, windings 49 are sequentially energized in one rotationaldirection only. Springs 69 and 71 are deflected only to the extentnecessary to overcome the drag of basket 31. The basket then spins withthe agitator 35 and rotor 51. It will thus be noted that both theagitation and the spin dry operations are accomplished without the useof clutches or other motion transfer devices. Rather, the samemechanical connections always exist between agitator 35 and basket 31with the resiliency of springs 69 and 71 providing the decoupling foroscillatory motions which is needed for agitation.

While spiral springs 69' and 71 have been shown by way of illustration,it should be understood that other types of decoupling or energy storingspring means could also be used. One such alternate construction isshown in FIG. 4 wherein tension springs are employed. The apparatus isshown from the bottom, looking up at the clothes holding basket 31. Acrank member 101 having a pair of arms 103 and 105 is secured toagitator shaft 25 by a pin 107. Each of arms 103 and 105 includes anattachment pin 109. A helical tension spring 111 extends from each suchpin to a post 113 set into basket 31 near its periphery. It will beapparent to those skilled in the art that, in this modification also,the agitator assembly and the springs 111 constitute 'a resonant oroscillatory system and that, when the agitator is displaced inoscillation, energy will be alternately stored and released by springs111 so as to reduce the peak torque required from the actuator whichdrives the agitator.

In view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous results attained.

As various changes could be made in the above constructions withoutdeparting from the scope of the invention, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

What is claimed is:

1. A washing machine comprising:

a tub;

a basket journalled for rotation within said tub;

an agitator journalled for rotation within 'said basket;

reversible electromagnetic drive means including a rotor which isdirectly and positively coupled to said agitator; and torsion springmeans interconnecting said basket and said agitator, wherebyunidirectional operation of said drive means produces rotation of saidbasket for moisture extraction by spinning and periodically reversingoperation of said drive means produces oscillation of said agitator withsaid basket being decoupled from the oscillatory movement of saidagitator by said spring means. 2. A washing machine according to claim 1in which said torsion spring means comprises a pair of oppositely woundspiral springs.

References Cited UNITED STATES PATENTS 2,588,963 3/1952 Ch-apin 68-232,660,044 11/1953 Williams 6823 WILLIAM I. PRICE, Primary Examiner.

WALTER SCHEEL, Examiner.

1. A WASHING MACHINE COMPRISING: A TUB; A BASKET JOURNALLED FOR ROTATIONWITHIN SAID TUB; AN AGITATOR JOURNALLED FOR ROTATION WITHIN SAID BASKET;REVERSIBLE ELECTROMAGNETIC DRIVE MEANS INCLUDING A ROTOR WHICH ISDIRECTLY AND POSITIVELY COUPLED TO SAID AGITATOR; AND TORSION SPRINGMEANS INTERCONNECTING SAID BASKET AND SAID AGITATOR, WHEREBYUNIDIRECTIONAL OPERATION OF SAID DRIVE MEANS PRODUCE ROTATION OF SAIDBASKET FOR MOISTURE EXTRACTION BY SPINNING AND PERIODICALLY REVERSINGOPERATION OF SAID DRIVE MEANS PRODUCES OSCILLATION OF SAID AGITATOR WITHSAID BASKET BEING DECOUPLED FROM THE OSCILLATORY MOVEMENT OF SAIDAGITATOR BY SAID SPRING MEANS.